/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.tomcat.util.modeler;

import javax.management.ObjectName;
import java.util.List;

/**
 * Interface for modeler MBeans.
 * <p>
 * This is the main entry point into modeler. It provides methods to create
 * and manipulate model mbeans and simplify their use.
 * <p>
 * Starting with version 1.1, this is no longer a singleton and the static
 * methods are strongly deprecated. In a container environment we can expect
 * different applications to use different registries.
 *
 * @author Craig R. McClanahan
 * @author Costin Manolache
 * @since 1.1
 */
public interface RegistryMBean {

	/**
	 * Load an extended mlet file. The source can be an URL, File or
	 * InputStream.
	 * <p>
	 * All mbeans will be instantiated, registered and the attributes will be
	 * set. The result is a list of ObjectNames.
	 *
	 * @param source InputStream or URL of the file
	 * @param cl     ClassLoader to be used to load the mbeans, or null to use the
	 *               default JMX mechanism ( i.e. all registered loaders )
	 * @return List of ObjectName for the loaded mbeans
	 * @throws Exception
	 * @since 1.1
	 */
	public List<ObjectName> loadMBeans(Object source, ClassLoader cl)
			throws Exception;

	/**
	 * Invoke an operation on a set of mbeans.
	 *
	 * @param mbeans    List of ObjectNames
	 * @param operation Operation to perform. Typically "init" "start" "stop" or "destroy"
	 * @param failFirst Behavior in case of exceptions - if false we'll ignore
	 *                  errors
	 * @throws Exception
	 */
	public void invoke(List<ObjectName> mbeans, String operation, boolean failFirst)
			throws Exception;

	/**
	 * Register a bean by creating a modeler mbean and adding it to the
	 * MBeanServer.
	 * <p>
	 * If metadata is not loaded, we'll look up and read a file named
	 * "mbeans-descriptors.ser" or "mbeans-descriptors.xml" in the same package
	 * or parent.
	 * <p>
	 * If the bean is an instance of DynamicMBean. it's metadata will be converted
	 * to a model mbean and we'll wrap it - so modeler services will be supported
	 * <p>
	 * If the metadata is still not found, introspection will be used to extract
	 * it automatically.
	 * <p>
	 * If an mbean is already registered under this name, it'll be first
	 * unregistered.
	 * <p>
	 * If the component implements MBeanRegistration, the methods will be called.
	 * If the method has a method "setRegistry" that takes a RegistryMBean as
	 * parameter, it'll be called with the current registry.
	 *
	 * @param bean  Object to be registered
	 * @param oname Name used for registration
	 * @param type  The type of the mbean, as declared in mbeans-descriptors. If
	 *              null, the name of the class will be used. This can be used as a hint or
	 *              by subclasses.
	 * @since 1.1
	 */
	public void registerComponent(Object bean, String oname, String type)
			throws Exception;

	/**
	 * Unregister a component. We'll first check if it is registered,
	 * and mask all errors. This is mostly a helper.
	 *
	 * @param oname
	 * @since 1.1
	 */
	public void unregisterComponent(String oname);

	/**
	 * Return an int ID for faster access. Will be used for notifications
	 * and for other operations we want to optimize.
	 *
	 * @param domain Namespace
	 * @param name   Type of the notification
	 * @return An unique id for the domain:name combination
	 * @since 1.1
	 */
	public int getId(String domain, String name);

	/**
	 * Reset all metadata cached by this registry. Should be called
	 * to support reloading. Existing mbeans will not be affected or modified.
	 * <p>
	 * It will be called automatically if the Registry is unregistered.
	 *
	 * @since 1.1
	 */
	public void stop();

	/**
	 * Load descriptors. The source can be a File, URL pointing to an
	 * mbeans-descriptors.xml.
	 * <p>
	 * Also ( experimental for now ) a ClassLoader - in which case META-INF/ will
	 * be used.
	 *
	 * @param source
	 */
	public void loadMetadata(Object source) throws Exception;
}
